Field of the Invention
This invention relates to purification of waste water obtained during the production of an ester plasticizer through esterification of a polybasic carboxylic acid with an aliphatic alcohol. More particularly, this invention is directed to removing organic components from waste water and returning them to an esterification process whereby to leave behind water which can be readily purified so that it meets environmental standards and can be discharged. The present invention is particularly concerned with decreasing the biological oxygen demand of a waste water effluent from an ester plasticizer production process.